Clinical and economic outcomes attributable to carbapenem-resistant Enterobacterales and delayed appropriate antibiotic therapy in hospitalized patients

Risk Factors Analysis and Prediction Model Establishment for Carbapenem-Resistant Enterobacteriaceae Colonization: A Retrospective Cohort Study

Purpose

The objective of this study was to identify the risk factors associated with Carbapenem-resistant Enterobacteriaceae (CRE) colonization in intensive care unit (ICU) patients and to develop a predictive risk model for CRE colonization.

Patients and Methods

In this study, 121 ICU patients from Fujian Provincial Hospital were enrolled between January 2021 and July 2022. Based on bacterial culture results from rectal and throat swabs, patients were categorized into two groups: CRE-colonized (n = 18) and non-CRE-colonized (n = 103). To address class imbalance, Synthetic Minority Over-sampling Technique (SMOTE) was applied. Statistical analyses including T-tests, Chi-square tests, and Mann-Whitney U-tests were employed to compare differences between the groups. Feature selection was performed using Lasso regression and Random Forest algorithms. A Logistic regression model was then developed to predict CRE colonization risk, and the results were presented in a nomogram.

Results

After applying SMOTE, the dataset included 198 CRE-colonized patients and 180 non-CRE-colonized patients, ensuring balanced groups. The two groups were comparable in most clinical characteristics except for diabetes, previous emergency department admission, and abdominal infection. Eight independent risk factors for CRE colonization were identified through Random Forest, Lasso regression, and Logistic regression, including Acute Physiology and Chronic Health Evaluation (APACHE) II score > 16, length of hospital stay > 31 days, female gender, previous carbapenem antibiotic exposure, skin infection, multi-site infection, immunosuppressant exposure, and tracheal intubation. The risk prediction model for CRE colonization demonstrated high accuracy (87.83%), recall rate (89.9%), precision (85.6%), and an AUC value of 0.877. Patients were categorized into low-risk (0-90 points), medium-risk (91-160 points), and high-risk (161-381 points) groups, with corresponding CRE colonization rates of 1.82%, 7.14%, and 58.33%, respectively.

Conclusion

This study identified independent risk factors for CRE colonization and developed a predictive model for assessing the risk of CRE colonization.

Phenotypic and genotypic antibiotic susceptibility profiles of Gram-negative bacteria isolated from bloodstream infections at a referral hospital, Lusaka, Zambia

Bloodstream infections (BSI) caused by antimicrobial-resistant (AMR) Gram-negative bacteria (GNB) are a significant cause of morbidity and mortality. Third-generation cephalosporins (3GCs) have been used as empiric treatment for BSI and other invasive infections for years; however, their overuse could promote the emergence of extended-spectrum beta-lactamases (ESBLs). Thus, this study aimed to determine the epidemiological, clinical and microbiological features and the effects of antimicrobial resistance on the outcomes of BSIs at a referral hospital in Lusaka, Zambia. This was a six-month prospective facility-based study undertaken at a referral hospital in Lusaka, Zambia. As part of the routine diagnosis and patient care, blood samples for bacteriological culture were collected from patients presenting with fever and processed for pathogen identification and antimicrobial susceptibility testing using the VITEK 2 Compact instrument. ESBLs and plasmid-mediated quinolone resistance (PMQR) associated genes were determined using the polymerase chain reaction method. Patient information was collected using a structured data collection sheet and entered in CSpro 7.6. Data were analysed in WHOnet and STATA version 14. A total of 88 GNB were isolated, of which 76% were Enterobacterales, 14% Acinetobacter baumannii and 8% Pseudomonas aeruginosa. Resistance to third and fourth-generation cephalosporins was 75% and 32%, respectively. Noteworthy was the high prevalence (68%) of inappropriate empirical treatment, carbapenem resistance (7%), multi-drug resistance (83%) and ESBL-producers (76%). In comparison to E. coli as a causative agent of BSI, the odds of death were significantly higher among patients infected with Acinetobacter baumannii (OR = 3.8). The odds of death were also higher in patients that received 3GCs as empiric treatment than in those that received 4GCs or other (none cephalosporin) treatment options. Structured surveillance, yearly antibiogram updates, improved infection control and a well functional antimicrobial stewardship (AMS) program, are of utmost importance in improving appropriate antimicrobial treatment selection and favourable patient outcomes.

The burden of carbapenem-resistant Enterobacterales infection in a large Thai tertiary care hospital

Background: Carbapenem-resistant Enterobacterales (CRE) are resistant to several other classes of antimicrobials, reducing treatment options and increasing mortality. We studied the clinical characteristics and burden of hospitalized adult patients with CRE infections in a setting where treatment options are limited.

Methods: A retrospective cohort study included adult inpatients between January 2015–December 2019 at Siriraj Hospital in Bangkok, Thailand. Clinical and microbiological data were reviewed.

Results: Of 420 patients with CRE infections, the mean age was 65.00 ± 18.89 years, 192 (45.72%) were male, and 112 (26.90%) were critically ill. Three hundred and eighty (90.48%) had Klebsiella pneumoniae, and 40 (9.52%) had Escherichia coli infections. The mean APACHE II score was 14.27 ± 6.36. Nearly half had previous hospitalizations (48.81%), 41.2% received antimicrobials, and 88.1% had undergone medical procedures before the onset of infection. The median time of onset of CRE infection was 16 days after admission. Common sites of infection were bacteremia (53.90%) and pneumonia (45.47%). Most CRE-infected patients had septic shock (63.10%) and Gram-negative co-infections (62.85%). Colistin (29.95%) and non-colistin (12.91%) monotherapies, and colistin-based (44.78%) and non-colistin-based (12.36%) combination therapies were the best available antimicrobial therapies (BAAT). The median length of hospitalization was 31 days, and the median hospitalization cost was US$10,435. The in-hospital mortality rate was 68.33%. Septic shock [adjusted odds ratio (aOR) 10.73, 5.65–20.42, p <0 .001], coinfection (aOR 2.43, 1.32–4.47, p = 0.004), mechanical ventilation (aOR 2.33, 1.24–4.36, p = 0.009), and a high SOFA score at onset (aOR 1.18, 1.07–1.30, p <0 .001) were associated with mortality.

Conclusion: CRE infection increases mortality, hospital stays, and healthcare costs. A colistin-based regimen was the BAAT in this study. Therefore, newer antimicrobial agents are urgently needed.